CN102824924A - Mesoporous solid strong base catalyst, preparation method and application - Google Patents

Abstract

The invention discloses a mesoporous solid strong base catalyst, a preparation method and an application. The solid base catalyst adopts a strategy of multi-layer plating to avoid the corrosion of the carrier by strong alkaline species, and can catalyze the transesterification reaction under mild conditions, especially the reaction of synthesizing dimethyl carbonate by transesterification. The mesoporous solid strong base catalyst of the present invention is composed of a mesoporous carrier, a decorative coating capable of protecting the pore structure of the mesoporous carrier, and a strong base, wherein the decorative coating is zirconia or carbon, and the strong base The content of active substances is 0.5~7.6mmol·g ^-1 .

Description

A kind of mesoporous solid strong base catalyst, preparation method and application

technical field

The invention relates to a catalyst, a preparation method and an application, a mesoporous solid strong base catalyst, a preparation method and an application.

Background technique

Mesoporous solid strong alkali material is widely used in the production of petrochemical and fine chemicals. It can catalyze various reactions under milder conditions, has low corrosion to equipment, and can be recycled, which meets the requirements of energy saving and environmental protection. The requirement of protecting the environment, it is convenient to realize the continuous process in the production process, and the application prospect is very broad.

Mesoporous silica has low cost, high stability, and controllable pore structure, so mesoporous silica is an ideal solid alkali carrier. However, if a strong base site is directly introduced onto the mesoporous silica, the base site will react with the mesoporous silica, which not only fails to generate a strong base site, but also destroys the mesoporous structure of the carrier.

For example: dimethyl carbonate (DMC) is a green and environmentally friendly chemical product that has attracted much attention at home and abroad. Because of its structure containing methoxy and carbonyl, it is expected to replace highly toxic or carcinogenic substances such as phosgene for carbonylation, formazan, etc. Reactions such as alkylation and transesterification to prepare many important chemical products. The transesterification method is an important method for the synthesis of dimethyl carbonate, and its mild reaction conditions, non-toxic process and high selectivity have become a method with great application prospects. Solid base catalyst is the core technology for the synthesis of DMC by transesterification. Therefore, the development of new and efficient solid base catalyst materials has attracted much attention.

Based on the above problems, it is necessary to develop a mesoporous solid strong base catalyst, which can be introduced into the plating layer before the introduction of basic sites. corrosion.

Contents of the invention

The object of the present invention is to provide a kind of mesoporous solid strong base catalyst, as the catalyst of transesterification reaction. The solid base catalyst adopts a strategy of multi-layer plating to avoid corrosion of the support by strong alkaline species. The solid base can catalyze the transesterification reaction to synthesize dimethyl carbonate under mild conditions.

Another object of the present invention is to provide the preparation method of the above-mentioned mesoporous solid strong base catalyst; meanwhile, the present invention also provides the application of the catalyst in the transesterification reaction.

The present invention is achieved through the following technical solutions:

The mesoporous solid strong base catalyst of the present invention is composed of a mesoporous carrier, a decorative coating capable of protecting the pore structure of the mesoporous carrier, and a strong base, wherein the decorative coating is zirconia or carbon, and the strong base The content of active substances is 0.5~7.6mmol·g ^-1 .

Mesoporous solid strong base catalyst of the present invention, its further technical scheme is that described mesoporous carrier is one or more compositions in mesoporous silica SBA-15, MCM-41, MCM-48; Further The technical solution is that the mesoporous silicon oxide is prepared by using tetraethylorthosilicate as the silicon source and a surfactant as a template through a self-assembly method, and the template agent is roasted and removed in an air atmosphere.

The further technical scheme of the mesoporous solid strong base catalyst of the present invention can also be that one or more of zirconium oxynitrate, zirconium oxychloride, and zirconium nitrate is used as a precursor when the described decorative layer is zirconia introduction; when the decorative plating layer is carbon, one or more of furanyl alcohol, sucrose, and phenolic resin is used as a precursor for introduction.

The further technical scheme of the mesoporous solid strong base catalyst of the present invention can also be that the strong base is introduced by the alkali precursor by wet impregnation, and the alkali precursor is lithium nitrate, sodium nitrate, potassium nitrate , rubidium nitrate, cesium nitrate, magnesium nitrate, calcium nitrate, strontium nitrate, barium nitrate and one or more of the corresponding acetate.

The preparation method of the above-mentioned mesoporous solid strong base catalyst of the present invention includes the synthesis of mesoporous carrier, the introduction of a plating layer capable of protecting the pore structure of the mesoporous carrier and the introduction of strong alkali, wherein:

When the decorative layer that can protect the pore structure of the mesoporous carrier is zirconia, its introduction method is as follows: Weigh the precursor and dissolve it in deionized water, add the mesoporous carrier, stir at room temperature for 12-24h in a water bath at 60-90°C Evaporate to dryness, then place the sample of the loaded precursor in an open container, and place the container in a polytetrafluoroethylene autoclave containing 14-28% ammonia by mass, while the ammonia solution and the solid are not in contact , put the sealed autoclave in an oven at 60-80°C for 0.5-1h, dry the processed sample at 60-120°C, put the obtained white powder in a tube furnace and ventilate it at 400-550°C Roast for 4-6 hours to obtain a zirconia plating layer that can protect the pore structure of the mesoporous carrier;

When the decorative plating layer capable of protecting the pore structure of the mesoporous carrier is carbon, its introduction method is as follows: the precursor and oxalic acid are dissolved in ethanol at a mass ratio of 10:1, and the mesoporous carrier is added, and heated at 70-90°C Stir at low temperature until the solution is evaporated to dryness, place the mixture in an oven at 140-170°C for pre-carbonization for 3-12 hours and vacuumize for 1-3 hours to remove unpolymerized precursors, and then transfer the vacuumized sample to a tube furnace Under the protection of an inert atmosphere, carbonize at 700-900°C for 3-5 hours to obtain a carbon plating layer that can protect the pore structure of the mesoporous carrier.

The preparation method of the mesoporous solid strong base catalyst of the present invention, its further technical scheme is that the introduction method of the strong base is to introduce by using the wet impregnation method of the base precursor, and the steps are as follows: Weigh the base precursor and dissolve it in deionized water , add the carrier with a plating layer that can protect the pore structure of the mesoporous carrier under stirring, stir at room temperature for 12-24 hours, evaporate to dryness in a 60-90°C water bath, and then dry in an oven at 80-120°C After 4-8 hours, activate the obtained sample under the protection of inert gas at 400-550°C to generate strong basic sites.

The above-mentioned mesoporous solid strong base catalyst of the present invention can be used in the transesterification reaction; A further technical scheme is the application of this mesoporous solid strong base catalyst in the preparation of dimethyl carbonate with ethylene carbonate and methanol as raw material The specific steps are as follows: methanol, ethylene carbonate and mesoporous solid strong base catalyst are put into a three-necked flask, the mol ratio of methanol and ethylene carbonate is 5:1, and the catalyst consumption is 0.2-5% of the raw material methanol quality, The reaction temperature is 60-80°C, the pressure is normal pressure, and after reflux and stirring for 0.5-4 hours, dimethyl carbonate is obtained through centrifugation.

Compared with the prior art, the present invention has the following beneficial effects:

The invention introduces a plating layer on the mesoporous silicon oxide, avoids direct contact between strong alkaline species and the carrier to corrode the carrier, effectively protects the mesoporous structure of the carrier, and prepares the mesoporous solid strong alkali catalyst. The solid base is used to catalyze the transesterification reaction, especially for the synthesis of dimethyl carbonate, the catalytic effect is relatively ideal, the catalytic operation can be carried out under mild conditions, and the operating cost is low.

Detailed ways

There are many carriers that can be used in the present invention, such as existing products such as SBA-15, MCM-41, and MCM-48. These materials are silicon oxides with regular mesoporous channels, which can be well combined with the introduced plating layer.

Alkaline precursors that can be used in the present invention can be selected from but not limited to lithium nitrate, sodium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, magnesium nitrate, calcium nitrate, strontium nitrate, barium nitrate and corresponding acetate, the introduced The amount can be adjusted within a certain range.

The decorative plating layer that can be used in the present invention can be selected from but not limited to zirconia and carbon, and the amount introduced can be adjusted within a certain range. The precursor of zirconia can be selected from but not limited to zirconium oxychloride, zirconium nitrate, zirconyl nitrate, preferably zirconyl nitrate; the precursor of carbon can be selected from but not limited to sucrose, furan methanol, phenolic resin, preferably furan methanol.

The following examples are used to further illustrate the present invention without limiting the present invention.

Example 1

Weigh 0.81g ZrO(NO ₃ ) ₂ and dissolve it in 10mL deionized water, add 1g SBA-15 under stirring state, stir at room temperature for 24h and evaporate to dryness in 80°C water bath. Then the sample (0.5g) of the loaded precursor is placed in an open container, and the container is placed in a polytetrafluoroethylene autoclave with a volume of 50mL containing 28% ammonia, and the ammonia solution and the solid are not in contact. Put the sealed autoclave in an oven at 60°C for 0.5h. The treated sample was placed at room temperature for 6 hours, dried at 100°C for 12 hours, and the obtained white powder was placed in a tube furnace and baked at 500°C for 5 hours to convert ZrO(NO ₃ ) ₂ into ZrO ₂ for plating layer, and the resulting sample is labeled ZS.

Weigh 0.25g of KNO ₃ and dissolve it in deionized water, add 0.75g carrier ZS under stirring state, stir at room temperature for 24h, place in 80°C water bath to evaporate to dryness, and then dry in 100°C oven for 4h to obtain The samples were placed in a tube furnace and activated with nitrogen at 550 °C for 2 h to decompose KNO ₃ . The alkali content of the solid base catalyst was 2.5 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir the reaction at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 30.1%.

Example 2

Weigh 0.25g of LiNO ₃ and dissolve it in deionized water, add 0.75g carrier ZS under stirring state, stir at room temperature for 24h, place in 80°C water bath to evaporate to dryness, and then dry in 100°C oven for 4h to obtain The sample was placed in a tube furnace and activated with nitrogen at 550 °C for 2 h to decompose LiNO ₃ . The alkali content of the solid base catalyst was 3.6 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4 hours under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 39.3%.

Example 3

Weigh 0.25g of NaNO ₃ and dissolve it in deionized water, add 0.75g carrier ZS under stirring, stir at room temperature for 24h, place in 80°C water bath to evaporate to dryness, and then dry in 100°C oven for 4h to obtain The samples were placed in a tube furnace and activated with nitrogen at 550 °C for 2 h to decompose NaNO ₃ . The alkali content of the solid base catalyst was 2.9 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4h under normal pressure. The supernatant was obtained by centrifugation and analyzed by gas chromatography. The yield of DMC was 33%.

Example 4

Weigh 0.25g of RbNO ₃ and dissolve it in deionized water, add 0.75g carrier ZS under stirring state, stir at room temperature for 24h, evaporate to dryness in 80°C water bath, and then dry in 100°C oven for 4h to obtain The samples were placed in a tube furnace and activated with nitrogen at 550 °C for 2 h to decompose RbNO ₃ . The alkali content of the solid base catalyst was 1.7 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir the reaction at 65°C for 4h under normal pressure. The supernatant was obtained by centrifugation and analyzed by gas chromatography. The yield of DMC was 27.4%.

Example 5

Weigh 0.25g of CsNO ₃ and dissolve it in deionized water, add 0.75g carrier ZS under stirring state, stir at room temperature for 24h, evaporate to dryness in 80°C water bath, and then dry in 100°C oven for 4h to obtain The samples were placed in a tube furnace with nitrogen gas and activated at 550 °C for 2 h to decompose CsNO ₃ . The alkali content of the solid base catalyst was 1.3 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 25.8%.

Example 6

Weigh 0.43g of Mg(NO ₃ ) ₂ ·6H ₂ O and dissolve it in deionized water, add 0.75g carrier ZS under stirring state, stir at room temperature for 24h, place in 80°C water bath and evaporate to dryness, then at 100°C After drying in an oven for 4 hours, the obtained sample was activated in a tube furnace at 550° C. for 2 hours with nitrogen gas, so as to decompose Mg(NO ₃ ) ₂ . The alkali content of the solid base catalyst was 3.3 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir the reaction at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 34.6%.

Example 7

Weigh 0.36g of Ca(NO ₃ ) ₂ ·4H ₂ O and dissolve it in deionized water, add 0.75g carrier ZS under stirring state, stir at room temperature for 24h, place in 80°C water bath and evaporate to dryness, then at 100°C After drying in an oven for 4 hours, the obtained sample was activated in a tube furnace at 550° C. for 2 hours with nitrogen gas to decompose Ca(NO ₃ ) ₂ . The alkali content of the solid base catalyst was 3.0 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 32.2%.

Example 8

Weigh 0.25g of Sr(NO ₃ ) ₂ and dissolve it in deionized water, add 0.75g carrier ZS under stirring, stir at room temperature for 24h, evaporate to dryness in 80°C water bath, and then dry in 100°C oven After 4 hours, the obtained sample was placed in a tube furnace and activated with nitrogen gas at 550° C. for 2 hours, so as to decompose Sr(NO ₃ ) ₂ . The alkali content of the solid base catalyst was 2.4 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4 hours under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 30%.

Example 9

Weigh 0.25g of Ba(NO ₃ ) ₂ and dissolve it in deionized water, add 0.75g carrier ZS under stirring, stir at room temperature for 24h, evaporate to dryness in 80°C water bath, and then dry in 100°C oven After 4 hours, the obtained sample was placed in a tube furnace and activated with nitrogen gas at 550° C. for 2 hours to decompose Ba(NO ₃ ) ₂ . The alkali content of the solid base catalyst was 1.9 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4 hours under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 26.2%.

Example 10

Dissolve 0.4g of furan methanol and 0.04g of oxalic acid in 5mL of ethanol, add 1g of SBA-15, stir at 80°C until the solution is evaporated to dryness, place the mixture in an oven at 150°C for pre-carbonization for 3 hours and then vacuum for 3 hours to remove Unpolymerized furanmethanol. Finally, the vacuumized sample was transferred to a tube furnace, and carbonized at 700 °C for 3 h under the protection of an inert atmosphere, and the carbonized sample was marked as CS.

Weigh 0.2g of KNO ₃ and dissolve it in deionized water, add 0.8g carrier CS under stirring state, stir at room temperature for 24h, place in 80°C water bath to evaporate to dryness, and then dry in 100°C oven for 4h to obtain The samples were placed in a tube furnace and activated with nitrogen at 400 °C for 2 h to decompose KNO ₃ . The alkali content of the solid base catalyst was 1.9 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir the reaction at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 29.8%.

Example 11

Weigh 0.2g of LiNO ₃ and dissolve it in deionized water, add 0.8g carrier CS under stirring state, stir at room temperature for 24h, evaporate to dryness in 80°C water bath, and then dry in 100°C oven for 4h to obtain The sample was placed in a tube furnace with nitrogen and activated at 400 °C for 2 h to decompose LiNO ₃ . The alkali content of the solid base catalyst was 2.9 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 37%.

Example 12

Weigh 0.2g of NaNO ₃ and dissolve it in deionized water, add 0.8g carrier CS under stirring state, stir at room temperature for 24h, place in 80°C water bath to evaporate to dryness, and then dry in 100°C oven for 4h to obtain The samples were placed in a tube furnace and activated with nitrogen at 400 °C for 2 h to decompose NaNO ₃ . The alkali content of the solid base catalyst was 2.3 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir the reaction at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 30.2%.

Example 13

Weigh 0.2g of RbNO ₃ and dissolve it in deionized water, add 0.8g carrier CS under stirring state, stir at room temperature for 24h, place in 80°C water bath to evaporate to dryness, and then dry in 100°C oven for 4h to obtain The samples were activated in a tube furnace with nitrogen at 400 °C for 2 h to decompose RbNO ₃ . The alkali content of the solid base catalyst was 1.4 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4h under normal pressure. The supernatant was obtained by centrifugation and analyzed by gas chromatography. The yield of DMC was 22%.

Example 14

Weigh 0.2g of CsNO ₃ and dissolve it in deionized water, add 0.8g carrier CS under stirring state, stir at room temperature for 24h, place in 80°C water bath to evaporate to dryness, and then dry in 100°C oven for 4h to obtain The samples were placed in a tube furnace with nitrogen and activated at 400 °C for 2 h to decompose CsNO ₃ . The alkali content of the solid base catalyst was 1.0 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4 hours under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 18.4%.

Example 15

Weigh 0.35g of Mg(NO ₃ ) ₂ ·6H ₂ O and dissolve it in deionized water, add 0.8g carrier CS under stirring state, stir at room temperature for 24h, place in 80°C water bath and evaporate to dryness, and then in 100°C After drying in an oven for 4 hours, the obtained samples were activated in a tube furnace at 400°C for 2 hours with nitrogen gas. The alkali content of the solid base catalyst was 2.6 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir the reaction at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 30.4%.

Example 16

Weigh 0.29g of Ca(NO ₃ ) ₂ ·4H ₂ O and dissolve it in deionized water, add 0.8g carrier CS under stirring state, stir at room temperature for 24h, place in 80°C water bath and evaporate to dryness, and then in 100°C After drying in an oven for 4 hours, the obtained samples were activated in a tube furnace at 400°C for 2 hours with nitrogen gas. The alkali content of the solid base catalyst was 2.4 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 28.4%.

Example 17

Weigh 0.2g of Sr(NO ₃ ) ₂ and dissolve it in deionized water, add 0.8g carrier CS under stirring, stir at room temperature for 24h, evaporate to dryness in 80°C water bath, and then dry in 100°C oven After 4h, the obtained sample was activated in a tube furnace at 400°C for 2h with nitrogen gas. The alkali content of the solid base catalyst was 1.9 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir the reaction at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 22.3%.

Example 18

Weigh 0.2g of Ba(NO ₃ ) ₂ and dissolve it in deionized water, add 0.8g carrier CS under stirring, stir at room temperature for 24h, evaporate to dryness in 80°C water bath, and then dry in 100°C oven After 4h, the obtained sample was activated in a tube furnace at 400°C for 2h with nitrogen gas. The alkali content of the solid base catalyst was 1.5 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 19.2%.

Example 19

Weigh 0.47g of ZrO(NO ₃ ) ₂ and dissolve it in 10mL of deionized water, add 1g of MCM-41 under stirring, stir at room temperature for 24h and evaporate to dryness in a water bath at 80°C. Then the sample (0.5g) of the loaded precursor is placed in an open container, and the container is placed in a polytetrafluoroethylene autoclave with a volume of 50mL containing 28% ammonia, and the ammonia solution and the solid are not in contact. Put the sealed autoclave in an oven at 60°C for 0.5h. Afterwards, the treated sample was placed at room temperature for 6 hours, dried at 100°C for 12 hours, and the obtained white powder was placed in a tube furnace and calcined at 500°C for 5 hours to convert ZrO(NO ₃ ) ₂ into ZrO ₂ Plated decorative layer, the obtained sample is marked as ZS-1.

Weigh 0.25g of KNO ₃ and dissolve it in deionized water, add 0.75g of carrier ZS-1 under stirring, stir at room temperature for 24h, evaporate to dryness in a water bath at 80°C, and then dry in an oven at 100°C for 4h. The obtained samples were activated in a tube furnace with nitrogen gas at 550°C for 2 h to decompose KNO ₃ . The alkali content of the solid base catalyst was 2.5 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir the reaction at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 28.1%.

Example 20

Weigh 0.25g of LiNO ₃ and dissolve it in deionized water, add 0.75g of carrier ZS-1 under stirring, stir at room temperature for 24h, evaporate to dryness in a water bath at 80°C, and then dry in an oven at 100°C for 4h. The obtained sample was activated in a tube furnace with nitrogen gas at 550 °C for 2 h to decompose LiNO ₃ . The alkali content of the solid base catalyst was 3.6 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir the reaction at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 38.7%.

Example 21

Dissolve 0.4g of furan methanol and 0.04g of oxalic acid in 5mL of ethanol, add 1g of MCM-41, stir at 80°C until the solution is evaporated to dryness, place the mixture in an oven at 150°C for pre-carbonization for 3h, then vacuumize for 3h, remove Unpolymerized furanmethanol. Finally, the vacuumized sample was transferred to a tube furnace, and carbonized at 700°C for 3 hours under the protection of an inert atmosphere. The carbonized sample was designated as CS-1.

Weigh 0.2g of KNO ₃ and dissolve it in deionized water, add 0.8g of carrier CS-1 under stirring, stir at room temperature for 24h, evaporate to dryness in 80°C water bath, and then dry in 100°C oven for 4h. The obtained samples were activated in a tube furnace with nitrogen gas at 400°C for 2 h to decompose KNO ₃ . The alkali content of the solid base catalyst was 1.9 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 27.6%.

Example 22

Weigh 0.2g of LiNO ₃ and dissolve it in deionized water, add 0.8g carrier CS-1 under stirring, stir at room temperature for 24h, evaporate to dryness in 80°C water bath, and then dry in 100°C oven for 4h, The obtained samples were activated in a tube furnace with nitrogen at 400 °C for 2 h to decompose LiNO ₃ . The alkali content of the solid base catalyst was 2.9 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir the reaction at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 35.7%.

Example 23

Weigh 0.47g ZrO(NO ₃ ) ₂ and dissolve it in 10mL deionized water, add 1g MCM-48 under stirring state, stir at room temperature for 24h and evaporate to dryness in 80°C water bath. Then the sample (0.5g) of the loaded precursor is placed in an open container, and the container is placed in a polytetrafluoroethylene autoclave with a volume of 50mL containing 28% ammonia, and the ammonia solution and the solid are not in contact. Put the sealed autoclave in an oven at 60°C for 0.5h. Afterwards, the treated sample was placed at room temperature for 6 hours, dried at 100°C for 12 hours, and the obtained white powder was placed in a tube furnace and calcined at 500°C for 5 hours to convert ZrO(NO ₃ ) ₂ into ZrO ₂ Plating finish, the obtained sample is marked as ZS-2.

Weigh 0.25g of KNO ₃ and dissolve it in deionized water, add 0.75g carrier ZS-2 under stirring, stir at room temperature for 24h, evaporate to dryness in 80°C water bath, and then dry in 100°C oven for 4h. The obtained samples were activated in a tube furnace with nitrogen gas at 550°C for 2 h to decompose KNO ₃ . The alkali content of the solid base catalyst was 2.5 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4 hours under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 28.9%.

Example 24

Weigh 0.25g of LiNO ₃ and dissolve it in deionized water, add 0.75g of carrier ZS-2 under stirring, stir at room temperature for 24h, evaporate to dryness in a water bath at 80°C, and then dry in an oven at 100°C for 4h. The obtained sample was activated in a tube furnace with nitrogen gas at 550 °C for 2 h to decompose LiNO ₃ . The alkali content of the solid base catalyst was 3.6 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir the reaction at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 38.8%.

Example 25

Dissolve 0.4g of furan methanol and 0.04g of oxalic acid in 5mL of ethanol, add 1g of MCM-48, stir at 80°C until the solution is evaporated to dryness, place the mixture in an oven at 150°C for pre-carbonization for 3h, then vacuumize for 3h, remove Unpolymerized furanmethanol. Finally, the vacuumized sample was transferred to a tube furnace, and carbonized at 700°C for 3 hours under the protection of an inert atmosphere. The carbonized sample was designated as CS-2.

Weigh 0.2g of KNO ₃ and dissolve it in deionized water, add 0.8g of carrier CS-2 under stirring, stir at room temperature for 24h, evaporate to dryness in 80°C water bath, and then dry in 100°C oven for 4h. The obtained samples were activated in a tube furnace with nitrogen gas at 400°C for 2 h to decompose KNO ₃ . The alkali content of the solid base catalyst was 1.9 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir the reaction at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 26.6%.

Example 26

Weigh 0.2 g of LiNO ₃ and dissolve it in deionized water, add 0.8 g of carrier CS-2 under stirring, stir at room temperature for 24 h, evaporate to dryness in a water bath at 80 °C, and then dry in an oven at 100 °C for 4 h. The obtained samples were activated in a tube furnace with nitrogen at 400 °C for 2 h to decompose LiNO ₃ . The alkali content of the solid base catalyst was 2.9 mmol·g ^-1 .

Add 16g of methanol, 8.7g of ethylene carbonate and 0.08g of catalyst into the flask, and stir at 65°C for 4h under normal pressure. The supernatant is obtained by centrifugation and analyzed by gas chromatography. The yield of DMC is 33.4%.

Claims (10)

1. A mesoporous solid strong base catalyst is characterized in that this solid base catalyst is made of a mesoporous carrier, a decorative coating that can protect the mesoporous carrier channel structure and a strong base, wherein said decorative coating is an oxidation Zirconium or carbon, the content of the strong basic substance is 0.5~7.6mmol·g ^-1 . 2. The mesoporous solid strong base catalyst according to claim 1, characterized in that the mesoporous carrier is one or more of mesoporous silica SBA-15, MCM-41, and MCM-48. 3. The mesoporous solid strong base catalyst according to claim 2, characterized in that the mesoporous silica is based on tetraethyl orthosilicate as silicon source, with surfactant as template, through the method of self-assembly Preparation, the template agent is roasted and removed under air atmosphere. 4. The mesoporous solid strong base catalyst according to claim 1, wherein one or more of zirconium oxynitrate, zirconium oxychloride, and zirconium nitrate is used as a precursor when the described decorative layer is zirconium oxide body; when the plating layer is carbon, one or more of furanyl alcohol, sucrose, and phenolic resin is used as a precursor for introduction. 5. The mesoporous solid strong base catalyst according to claim 1, wherein said strong base is introduced by alkali precursor by wet impregnation, and said alkali precursor is lithium nitrate, sodium nitrate, potassium nitrate, One or more of rubidium nitrate, cesium nitrate, magnesium nitrate, calcium nitrate, strontium nitrate, barium nitrate and the corresponding acetate. 6. A method for preparing the mesoporous solid strong base catalyst as claimed in any one of claims 1-5, comprising the synthesis of mesoporous carrier, the introduction of the decorative plating layer and the introduction of strong alkali that can protect the mesoporous carrier pore structure, It is characterized by: When the decorative layer that can protect the pore structure of the mesoporous carrier is zirconia, its introduction method is as follows: Weigh the precursor and dissolve it in deionized water, add the mesoporous carrier, stir at room temperature for 12-24h in a water bath at 60-90°C Evaporate to dryness, then place the sample of the loaded precursor in an open container, and place the container in a polytetrafluoroethylene autoclave containing 14-28% ammonia by mass, while the ammonia solution and the solid are not in contact , put the sealed autoclave in an oven at 60-80°C for 0.5-1h, dry the processed sample at 60-120°C, put the obtained white powder in a tube furnace and ventilate it at 400-550°C Roast for 4-6 hours to obtain a zirconia plating layer that can protect the pore structure of the mesoporous carrier; When the decorative plating layer capable of protecting the pore structure of the mesoporous carrier is carbon, its introduction method is as follows: the precursor and oxalic acid are dissolved in ethanol at a mass ratio of 10:1, and the mesoporous carrier is added, and heated at 70-90°C Stir at low temperature until the solution is evaporated to dryness, place the mixture in an oven at 140-170°C for pre-carbonization for 3-12 hours and vacuumize for 1-3 hours to remove unpolymerized precursors, and then transfer the vacuumized sample to a tube furnace Under the protection of an inert atmosphere, carbonize at 700-900°C for 3-5 hours to obtain a carbon coating that can protect the pore structure of the mesoporous carrier. 7. the preparation method of mesoporous solid strong alkali catalyst according to claim 6 is characterized in that the introduction method of strong alkali is to adopt wet impregnation method to introduce by alkali precursor, and the steps are as follows: take alkali precursor and dissolve in In deionized water, add a carrier with a plating layer that can protect the pore structure of the mesoporous carrier under stirring, stir at room temperature for 12-24 hours, then place it in a water bath at 60-90°C to evaporate to dryness, and then dry it in an oven at 80-120°C Dry in medium temperature for 4-8h, and activate the obtained sample under the protection of inert gas at 400-550°C to generate strong basic sites. 8. The application of a mesoporous solid strong base catalyst as described in any one of claims 1-5 in transesterification. 9. the application of the mesoporous solid strong base catalyst according to claim 8 in the transesterification reaction is characterized in that it is the application in the preparation of dimethyl carbonate as raw material with ethylene carbonate and methyl alcohol. 10. the application of the mesoporous solid strong base catalyst according to claim 9 in the transesterification reaction is characterized in that the application in the preparation of dimethyl carbonate as raw material with ethylene carbonate and methyl alcohol mainly comprises the following steps : Put methanol, ethylene carbonate and mesoporous solid strong base catalyst into a three-necked flask, the mol ratio of methanol to ethylene carbonate is 5:1, the amount of catalyst is 0.2-5% of the raw material methanol quality, and the reaction temperature is 60 -80°C, the pressure is normal pressure, after reflux and stirring for 0.5~4h, dimethyl carbonate is obtained by centrifugation.